Adjustable head support for a chair

ABSTRACT

The head support unit may be attached by attachment means ( 13 ) to a chair, e.g. a wheel chair. A set screw ( 15 ) permits vertical adjustment. The head rest ( 19 ) may be horizontally moved by the user into the desired position. This movement takes place without a recognizable movement in vertical direction. The head rest ( 19 ) is carried by a slender lever parallelogram ( 18 ) which is operatively connected by a flexible Bowden-cable ( 21 ) to the motor ( 23 ) located at a distance on the chair. This flexible connection ( 21 ) permits not only to put the motor ( 23 ) at a suitable location away from the head of the user, but does also not hinder a vertical adjustment of the head rest ( 19 ) by means of the vertical support bar ( 11 ) and the set screw ( 15 ).

BACKGROUND OF THE INVENTION

The present invention is directed to an adjustable head support for a chair, in particular for a wheel chair or a raising wheel chair.

The U.S. Pat. No. 5,366,036 discloses a wheel chair, and more particularly a wheel chair which can elevate its occupant from a sitting position to a standing position. On a vertically adjustable rod or support bar a piece of square tube is welded in which a square tube on which a head rest is mounted can be horizontally moved and arrested at the desired position. It has the disadvantage that for the user sitting in the wheel chair it is not possible to adjust the head rest.

U.S. Pat. No. 3,730,589 discloses a wheel chair provided with a vertical bar on which a head rest is connected with a clamp. This clamp is of a design permitting vertical and horizontal adjustment of the head rest. In the vertical plane also an angular adjustment of- the head rest is possible (column 2, line 65 to column 3, line 5). These adjustments, however, can not be made by the user sitting in the wheel chair.

U.S. Pat. No. 6,726,280 does not disclose a head rest, but a back support. It comprises a mechanism in form of a lever parallelogram for simultaneously adjusting the back rest in vertical and horizontal direction. However, for a head rest this is not desirable, because the user of the wheel chair should be able to make an adjustment in the horizontal direction independently from an adjustment in the vertical direction.

The U.S. Pat. No. 6,550,856 discloses a mechanism having the same disadvantage like the mechanism just described. The headrest is laterally connected by a lever parallelogram to the seat back of a vehicle seat. Accordingly, when the seat back is forwardly tilted the head rest is moved also downward in order to reduce the total length of the seat back so that the head rest does not collide with the roof liner or the sun visor (column 1, lines 28 to 32, FIG. 3 a). For a wheelchair this design is not suitable. It has also the disadvantage that the head rest can not be removed.

SUMMARY OF THE INVENTION

It is thus the object of the invention to disclose an improved adjustable head support, which can easily be adjusted by the user of the chair, particularly the wheelchair. It should also conform to aesthetic requirements. The adjustable head rest support should permit adjustment in one direction, for example in horizontal direction, without causing a susceptible movement in an other direction.

This objective is obtained by an adjustable head support comprising a head rest, a vertical support bar for the head rest, means for attaching the vertical support bar to the chair, an adjusting mechanism for adjusting the horizontal position of the head rest, said adjusting mechanism comprising at least one lever pivotally connected to the upper portion of said vertical support bar and extending substantially vertically from the top of the vertical support bar to the headrest, an actuator for the adjusting mechanism and a linkage between the actuator and the adjusting mechanism. Because the adjusting mechanism for adjusting the horizontal position of the head rest is located on the top of the vertical support bar, a horizontal adjustment of the head rest does not cause a vertical movement recognizable by the user of the chair, this in contrast to the Prior Art according to U.S. Pat. No. 6,550,856. For the same reason a slim and well formed design of the head support is possible. To this contributes the fact that the actuator can be located away from the head of the user at a suitable location on the chair. A further advantage consists in that the vertical support bar together with the adjusting mechanism and the head rest can easily be removed, e.g. for transportation.

The linkage between the actuator and the adjusting mechanism could be a rod or lever. However, as the head rest should be easily adjustable in vertical direction, this may not be very practical. Accordingly, it is preferable to use a flexible device, for example a Bowden-cable. This allows easy adjusting of the head rest in vertical direction.

The adjusting mechanism may comprises a single lever which at the top is connected to the head rest. Preferably, a lever parallelogram is provided because it permits a movement of the head rest better adapted to the anatomy of the user. The connection of the adjusting mechanism with the head rest may be rigid or pivotal. Camp means may be provided to arrest the pivotal connection when the head rest is in the desired position.

Preferably, the lever parallelogram comprises a first and a second lever spaced from each other and pivotally connected at substantially the same height to the vertical support. The distance between the pivotal connection of the first and the second lever may be variable. This permits to adapt the movement of the head rest to the anatomy of the user. The levers of the adjusting mechanism may be overlapping. Accordingly, there is no danger of getting fingers or objects grabbed in between. Because the adjusting mechanism may be of slender design it can easily be enclosed by a flexible cover. This contributes to the nice appearance of the adjustable head support. The same is true for the possibility of using curved levers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an adjustable head support attached to a chair.

FIG. 2 shows a side elevation of the adjustable head support according to FIG. 1.

FIG. 3 shows a perspective view of the adjustable head support according to FIGS. 1 and 2.

FIG. 4 a to 4 c represent different horizontal positions of the head rest.

DETAILED DESCRIPTION OF THE INVENTION

The head rest unit 10 shown in the FIGS. 1 to 3 comprises a vertical adjustable support bar which can be moved vertically in a guide 13, which is attachable to the chair 12. The support bar 13 can be arrested in the desired position by a set screw 15 or the like. The support bar 11 is at the top provided with a plate 17 carrying the mechanism 18 for horizontal adjustment of a head rest 19. The device 18 is a lever mechanism connected by a mechanical connection device 21 to an actuator 23, e.g. a linear motor. The actuator 23 can be remote controlled by the user of the chair. In the embodiment shown the connection device 21 is a so called Bowden-cable. As is well known, a Bowden-cable comprises a wire 25 and a sheating 27.

The lever mechanism 18 may have a single lever connected to the head rest 19. However, on the embodiment shown the lever mechanism 18 is a lever parallelogram. This lever parallelogram 18 comprises a first lever 33 and a second lever 35 which have a curved form and are overlapping each other in every position of the lever parallelogram (FIG. 4 a to 4 c). The levers 33, 35 may be enclosed by a cover (not shown). The first lever 33 is pivotally connected with its lower end at 37 to the plate 17 and with the upper end at 39 to the connecting lever 45. The second lever 35 is with the lower end privotally connected at 41 to the plate 17 and with the upper end at 43 to the connecting lever 45. It is possible to provide different pivot points, that is different holes, at the connecting lever 45, so that the distance between the pivot points may be changed. The connecting lever 45 may consist of two parts connected by screws so as to permit to change of the distance between the pivot points 39 and 43.

The head rest 19 is rigidly or with an articulation 46 connected to the connection lever 45.

As already, described before, a Bowden-cable 21 connects the linear motor 23 with the lever mechanism 18. On the side of the linear motor 23 the sheating 27 of the Bowden-cable 21 is connected to a movable part 29 of the linear motor, the wire 25, however, to a stationary part 31. On the side of the lever mechanism the sheating 27 of the Bowden-cable 21 is connected to the arm 47 of the two-armed first lever 33. The wire 25 is led over a roller or pin 49 of the second lever 35 and is also connected to the arm 47.

Accordingly, when the linear motor 23 is actuated, its movable part 29 moves downward so that the lever 33 is moved clockwise (FIG. 4 b and FIG. 4 c). However, when the movable part 29 moves again upward, the head rest 19 moves, pulled by the spring 51 (FIG. 2), backward into the position of FIG. 4 a. 

1. An adjustable head support for attachment to chairs, in particular wheelchairs or raising wheelchairs, comprising a head rest, a vertical support bar for the head rest, means for attaching the vertical support to the chair a mechanism for adjusting the horizontal position of the head rest, said adjusting mechanism comprising at least one lever pivotally connected to upper portion of said vertical support bar and extending substantially vertically from to top of the vertical support bar to the head rest an actuator for the adjusting mechanism, a linkage between the actuator and the adjusting mechanism.
 2. The adjustable head support according to claim 1, wherein the adjusting mechanism is a lever parallelogram.
 3. The adjustable head support according to claim 2, wherein the lever parallelogram comprises a first and a second lever spaced from each other and pivotally connected at substantially the same height to the vertical support bar.
 4. The adjustable head support according to claim 3, wherein the distance between the pivotal connections of the first and second lever is variable.
 5. The adjustable head support according to claim 3, wherein the first and second lever are curved.
 6. The adjustable head support according to claim 3, wherein the first and the second lever are overlapping.
 7. The adjustable head support according to claim 3, wherein the adjusting mechanism is enclosed by a flexible cover.
 8. The adjustable head support according to claim 1, wherein the vertical support bar is adjustable in height.
 9. The adjustable head support according to claim 1, wherein the linkage between the actuator and the adjusting mechanism is a Bowden cable. 